The operator uses knowledge of the factors that affect abrasion to control the polishing sequence of an amalgam restoration, a composite restoration, and a gold restoration in the following ways:
1. Amalgam Restoration: The operator uses knowledge of the hardness and roughness of the amalgam material to select the appropriate polishing instruments and sequence. The polishing sequence typically involves the use of coarse abrasives, such as diamond burs, to remove any rough surfaces, followed by finer abrasives, such as rubber cups and points, to achieve a smooth and polished surface. The operator must also consider the presence of any marginal ridges or overhangs that may require additional attention during the polishing process.
2. Composite Restoration: The operator uses knowledge of the composite material's relative softness and tendency to wear during polishing to select the appropriate polishing instruments and sequence. The polishing sequence typically involves the use of fine abrasives, such as diamond polishing pastes, to achieve a high gloss finish. The operator must also consider any surface irregularities or contouring that may require additional attention during the polishing process.
3. Gold Restoration: The operator uses knowledge of the gold alloy's relative hardness and resistance to wear during polishing to select the appropriate polishing instruments and sequence. The polishing sequence typically involves the use of progressively finer abrasives, such as pumice, tripoli, and rouge, to achieve a high luster finish. The operator must also consider any surface irregularities, such as porosity or pits, that may require additional attention during the polishing process.
In all three types of restorations, the operator must also consider factors such as the shape and size of the polishing instruments, the speed and pressure of the polishing handpiece, and the use of cooling water or lubricating agents to minimize heat generation and reduce the risk of damage to the restoration or surrounding tissues. By carefully controlling the polishing sequence and techniques, the operator can achieve a smooth, polished surface that is both aesthetically pleasing and functionally effective.